Power outage
A power outage (also called a powercut, a power out, a power failure, a power blackout, a power loss, or a blackout) is the loss of the
There are many causes of power failures in an electricity network. Examples of these causes include faults at
operation.Power failures are particularly critical at sites where the environment and public safety are at risk. Institutions such as
Types
Power outages are categorized into three different phenomena, relating to the duration and effect of the outage:
- A transient fault is a loss of power typically caused by a fault on a power line, e.g. a short circuit or flashover. Power is automatically restored once the fault is cleared.
- A brownout is a drop in voltage in an electrical power supply. The term brownout comes from the dimming experienced by incandescent lighting when the voltage sags. Brownouts can cause poor performance of equipment or even incorrect operation.
- Outages may last from a few minutes to a few weeks depending on the nature of the blackout and the configuration of the electrical network.
- A blackout is the total loss of power to a wider area and of long duration.[1] It is the most severe form of power outage that can occur. Blackouts which result from or result in power stations tripping are particularly difficult to recover from quickly.
Protecting the power system from outages
In
Under certain conditions, a network component shutting down can cause current fluctuations in neighboring segments of the network leading to a cascading failure of a larger section of the network. This may range from a building, to a block, to an entire city, to an entire electrical grid.
Modern power systems are designed to be resistant to this sort of cascading failure, but it may be unavoidable (see below). Moreover, since there is no short-term economic benefit to preventing rare large-scale failures, researchers have expressed concern that there is a tendency to erode the resilience of the network over time, which is only corrected after a major failure occurs. In a 2003 publication, Carreras and co-authors claimed that reducing the likelihood of small outages only increases the likelihood of larger ones.[2] In that case, the short-term economic benefit of keeping the individual customer happy increases the likelihood of large-scale blackouts.
The Senate Committee on Energy and Natural Resources held a hearing in October 2018 to examine "black start", the process of restoring electricity after a system-wide power loss. The hearing's purpose was for Congress to learn about what the backup plans are in the electric utility industry in the case that the electric grid is damaged. Threats to the electrical grid include cyberattacks, solar storms, and severe weather, among others. For example, the "Northeast Blackout of 2003" was caused when overgrown trees touched high-voltage power lines. Around 55 million people in the U.S. and Canada lost power, and restoring it cost around $6 billion.[3]
Protecting computer systems from power outages
Computer systems and other electronic devices containing logic circuitry are susceptible to data loss or hardware damage that can be caused by the sudden loss of power. These can include data networking equipment, video projectors, alarm systems as well as computers. To protect computer systems against this, the use of an uninterruptible power supply or 'UPS' can provide a constant flow of electricity if a primary power supply becomes unavailable for a short period of time. To protect against surges (events where voltages increase for a few seconds), which can damage hardware when power is restored, a special device called a surge protector that absorbs the excess voltage can be used.
Restoring power after a wide-area outage
Restoring power after a wide-area outage can be difficult, as power stations need to be brought back online. Normally, this is done with the help of power from the rest of the grid. In the total absence of grid power, a so-called black start needs to be performed to bootstrap the power grid into operation. The means of doing so will depend greatly on local circumstances and operational policies, but typically transmission utilities will establish localized 'power islands' which are then progressively coupled together. To maintain supply frequencies within tolerable limits during this process, demand must be reconnected at the same pace that generation is restored, requiring close coordination between power stations, transmission and distribution organizations.
Blackout inevitability and electric sustainability
Self-organized criticality
It has been argued on the basis of
While blackout frequency has been shown to be reduced by operating it further from its critical point, it generally is not economically feasible, causing providers to increase the average load over time or upgrade less often resulting in the grid moving itself closer to its critical point. Conversely, a system past the critical point will experience too many blackouts leading to system-wide upgrades moving it back below the critical point. The term critical point of the system is used here in the sense of statistical physics and nonlinear dynamics, representing the point where a system undergoes a phase transition; in this case the transition from a steady reliable grid with few cascading failures to a very sporadic unreliable grid with common cascading failures. Near the critical point the relationship between blackout frequency and size follows a power-law distribution.[6][8]
Leaders are dismissive of system theories that conclude that blackouts are inevitable, but do agree that the basic operation of the grid must be changed. The Electric Power Research Institute champions the use of smart grid features such as power control devices employing advanced sensors to coordinate the grid.[9] Others advocate greater use of electronically controlled high-voltage direct current (HVDC) firebreaks to prevent disturbances from cascading across AC lines in a wide area grid.[10]
OPA model
In 2002, researchers at
Mitigation of power outage frequency
The effects of trying to mitigate cascading failures near the critical point in an economically feasible fashion are often shown to not be beneficial and often even detrimental. Four mitigation methods have been tested using the OPA blackout model:[2]
- Increase critical number of failures causing cascading blackouts – Shown to decrease the frequency of smaller blackouts but increase that of larger blackouts.
- Increase individual power line max load – Shown to increase the frequency of smaller blackouts and decrease that of larger blackouts.
- Combination of increasing critical number and max load of lines – Shown to have no significant effect on either size of blackout. The resulting minor reduction in the frequency of blackouts is projected to not be worth the cost of the implementation.
- Increase the excess power available to the grid – Shown to decrease the frequency of smaller blackouts but increase that of larger blackouts.
In addition to the finding of each mitigation strategy having a cost-benefit relationship with regards to frequency of small and large blackouts, the total number of blackout events was not significantly reduced by any of the above-mentioned mitigation measures.[2]
A complex network-based model to control large cascading failures (blackouts) using local information only was proposed by A. E. Motter.[17]
In 2015, one of the solutions proposed to reduce the impact of power outage was introduced by M. S. Saleh.[9]
Key performance indicators
Utilities are measured on three specific performance measures:
- System Average Interruption Duration Index, measured in minutes
- Customer Average Interruption Duration Index, measured in minutes
- Customer Average Interruption Frequency Index
See also
- Energy crisis
- Brittle Power
- Coronal mass ejection
- Critical infrastructure protection
- Cyberattack
- Dumsor
- Electromagnetic pulse (EMP)
- Energy conservation
- Internet outage
- List of energy storage projects
- Outage management system
- Proactive cyber defence
- Renewable energy
- Rolling blackout
- Self-organized criticality control
- Smart grid
- Uninterruptible power supply
Major power outages
- List of major power outages
- 2019 Venezuelan blackouts
- 2019 Java blackout
- 2012 India blackouts
- 2003 Italy blackout
- 2011 Southwest blackout
- 2019 California power shutoffs
- February 13–17, 2021 North American winter storm
- New York City blackout of 1977
- Northeast blackout of 1965
- Northeast blackout of 2003
References
- ISBN 978-3-7322-9329-2.
- ^ a b c Carreras, B. A.; Lynch, V. E.; Newman, D. E.; Dobson, I. (2003). "Blackout Mitigation Assessment in Power Transmission Systems" (PDF). 36th Hawaii International Conference on System Sciences. Hawaii. Archived from the original (PDF) on April 1, 2011.
- ^ Kovaleski, Dave (October 15, 2018). "Senate Hearing Examines Electric Industry's Ability to Restore Power after System-wide Blackouts". Daily Energy Insider. Retrieved October 23, 2018.
- ^ Dobson, I.; Chen, J.; Thorp, J.; Carreras, B.; Newman, D. Examining Criticality of Blackouts in Power System Models with Cascading Events. 35th Annual Hawaii International Conference on System Sciences (HICSS'02), January 7–10, 2002. Big Island, Hawaii. Archived from the original on September 12, 2003. Retrieved August 17, 2003.
- ^ Carreras, B. A.; Lynch, V. E.; Dobson, I.; Newman, D. E. Dynamics, Criticality and Self-organization in a Model for Blackouts in Power Transmission Systems (PDF). Hawaii International Conference on Systems Sciences, January 2002, Hawaii. Archived from the original (PDF) on August 21, 2003.
- ^ (PDF) from the original on March 4, 2016.
- ^ Carreras, B. A.; Newman, D. E.; Dobson, I.; Poole, A. B. (2000). Initial Evidence for Self-Organized Criticality in Electric Power System Blackouts (PDF). Proceedings of Hawaii International Conference on System Sciences, January 4–7, 2000, Maui, Hawaii. Archived from the original (PDF) on March 29, 2003. Retrieved August 17, 2003.
- ^ PMID 17614690.
- ^ S2CID 25664994.
- S2CID 19389285. Retrieved June 24, 2012.
- ^ "Power Systems Engineering Research Center". Board of Regents of the University of Wisconsin System. 2014. Archived from the original on June 12, 2015. Retrieved June 23, 2015.
- (PDF) from the original on March 5, 2016.
- S2CID 7708994.
- .
- S2CID 3824371. Archived from the original(PDF) on April 24, 2017.
- .
- S2CID 4856492.
External links
- "Blackout", TED talkby Marc Elsberg
- "3 Major Problems in Restoring Power After a Black Out", Space Weather
- Motter, Adilson E.; Lai, Ying-Cheng (December 20, 2002). "Cascade-based attacks on complex networks" (PDF). Physical Review E. 66 (6): 065102. S2CID 17189308.
- Blackouts at How Stuff Works
- Design Discussion Primer – Power Outages and Emergencies